Induction heating of elongated metal billets is well known in the art. In a typical installation, a plurality of billets are fed in an end-to-end relationship through an induction heater assembly. The billets often become so hot during heating that incipient melting occurs. The flow of molten metal, known as scale, frequently contacts the surface of the adjacent, following billet causing adhesion between the two billets. As the first heated billet is removed from the heater, the following billet may stick to it resulting in incomplete heating of the second billet due to its shortened residency time within the heater. In some instances, this necessitates a repetition of the heating process for the following billet.
Although several methods of solving this problem have been introduced, they have either proven unsuccessful or economically prohibitive. One technique utilized a roller adjacent the exit of the heater provided with a bumpy surface. Another technique employed a cylindrical roller rotated about an eccentric axis parallel to the longitudinal axis of the roller. These techniques provided only limited movement of the removed billet in a vertical direction and did not provide satisfactory results. The failures of these techniques led those skilled in the art to a relatively costly and messy method of preparing the billets with a glaze prior to heating in an attempt to prevent adhesion resulting from the scale created during the heating process.
The present invention is directed towards an effective and inexpensive means for removing and separating billets in order to increase production efficiency in induction heating processes.
This invention digresses from the current trend of the skilled practitioner attempting to solve this problem and returns back to the general concept of using a roller to separate the billets. However, the roller surface is shaped and rotated in such a manner that it wobbles to provide radial forces on the end of the removed billet in a multitude of orbital directions, not just up and down. This technique has provided excellent results for separating the billets and may be employed at comparatively low cost. In the preferred embodiment, the roller is rotated about an axis skewed relative to the major longitudinal axis of the roller. Preferably, the roller surface is defined by a surface of revolution provided by a curve defined by two converging lines meeting at a trough. This provides the roller with a generally "hour glass" shape with two ramp surfaces alternatingly providing progressively increasing components of sideways motion to the end of the billet. In addition, the surface of the roller may be provided with protruberances spaced thereon providing intermittent spurts of exaggerated motion to the billet.